碳酸钙中空微球的仿生合成及机理分析

以氯化钙、碳酸钠为原料,以聚丙烯酰胺(PAM)和十二烷基硫酸钠(SDS)形成的PAM/SDS核壳状复合物为软模板,仿生合成了中空微球碳酸钙。以透射电子显微镜、选区电子衍射、扫描电子显微镜、X射线衍射仪进行了表征,结果表明,制备得到的中空碳酸钙直径3⁶μm,分散性良好,中空球的球壁完整,壁厚约500 nm,由506μm,分散性良好,中空球的球壁完整,壁厚约500 nm,由50⁷0 nm的纳米粒子聚集而成。实验考察了PAM、SDS浓度的变化对产品的影响,并探讨了中空碳酸钙微球的形成机理。结果表明,PAM、SDS对中空碳酸钙微球的形成起着重要的作用。     

碳酸钙中空微球的仿生合成及机理分析

以氯化钙、碳酸钠为原料,以聚丙烯酰胺(PAM)和十二烷基硫酸钠(SDS)形成的PAM/SDS核壳状复合物为软模板,仿生合成了中空微球碳酸钙。以透射电子显微镜、选区电子衍射、扫描电子显微镜、X射线衍射仪进行了表征,结果表明,制备得到的中空碳酸钙直径3~6μm,分散性良好,中空球的球壁完整,壁厚约500 nm,由50~70 nm的纳米粒子聚集而成。实验考察了PAM、SDS浓度的变化对产品的影响,并探讨了中空碳酸钙微球的形成机理。结果表明,PAM、SDS对中空碳酸钙微球的形成起着重要的作用。     

气体扩散法合成花状碳酸化羟基磷灰石微球

利用较为简单的气体扩散法合成出了花状的碳酸化羟磷灰石微球,研究了羟磷灰石微球的组成和表面活性剂三聚磷酸钠对其形貌的影响,并用扫描电子显微镜(SEM)、傅立叶转换红外光谱(FT-IR)、X射线衍射(XRD)等方法对所得产物进行了表征.研究结果显示,矿化时间的长短对晶体形貌无太大影响,而改变三聚磷酸钠的浓度则会导致晶体形貌发生变化.不同浓度下形成的生物矿物均是碳酸化羟基磷灰石,这是由CO32-取代羟基磷灰石中(PO4)的位点所产生的结果.     

花状球霰石碳酸钙微球的简易合成与表征

以十二烷基硫酸钠(SDS)为表面活性剂,以氯化钙、碳酸钠为原料,采用简单的复分解法成功制备了花状球霰石碳酸钙微球。利用扫描电镜(SEM)和X射线衍射仪(XRD)对样品进行了表征,结果表明花状碳酸钙微球分散性良好,直径为2~4μm,是由20~30 nm的粒子聚集而成的片状互相交叉在一起形成的插层状结构。研究了SDS质量浓度和碳酸钠溶液pH对产物形貌和结构的影响,初步探讨了花状球霰石碳酸钙微球的形成机理,结果表明SDS质量浓度、碳酸钠溶液pH均对碳酸钙的形状和结构产生影响。该研究为低成本合成球霰石碳酸钙提供了借鉴。     

气相扩散法合成不同形貌羟基磷灰石微球

利用简单的氨气扩散的方法分别合成出了花状多孔和空心微球羟基磷灰石,研究了磷酸根浓度和非离子表面活性剂PVA对最终产物羟基磷灰石形貌的影响,并用场发射扫描电子显微镜(FESEM)、傅里叶变换红外光谱(FT-IR)、X射线衍射等方法对所得产物进行了表征.研究结果显示,在不含有PVA的溶液中,最初形成的物质为无定形磷酸钙(ACP),其随后转变为花状羟基磷灰石;增加磷酸根的浓度而保持钙离子浓度不变,得到的最终产物为空心羟基磷灰石微球.在溶液中加入非离子表面活性剂PVA,无论是否改变磷酸根浓度,得到的产物均为花状羟基磷灰石.     

锶羟基磷灰石的荧光性能及药物缓释性能

为探索具有荧光性能的锶羟基磷灰石作为骨疾病治疗用药物载体材料的应用前景,以Ca(NO3)2.4H2O)、Sr(NO3)2、(NH4)2HPO4、柠檬酸三钠、十六烷基三甲基溴化铵为原料,在180℃水热处理24h,制得了不同掺锶量的羟基磷灰石。表征了锶羟基磷灰石微球的晶相、形貌、组成、比表面积和荧光性能;研究了以锶羟基磷灰石作为载体,溶菌酶为模型药物的缓释效果。结果表明:合成的产物为花束状羟基磷灰石微球,随着掺锶量的增大,锶羟基磷灰石单球形貌由短棒状变为片状再变为长棒状,而比表面积和荧光强度则先增大后减小。此外,锶羟基磷灰石作为药物载体的缓释速率和释放量,随着锶含量的增大,呈现先减小后增大的趋势。     

羟基磷灰石微球的制备方法

羟基磷灰石[Ca_5(PO_4)_3(OH),HA]是一种重要的生物医学材料,尤其是球形羟基磷灰石更兼具比表面积大、流动性好和载药量高等特点,使其非常适于作为硬组织修复的基础材料,本文对现有球形羟基磷灰石(HA)的制备方法进行了综述,对各种制备方法所得微球的结构和尺寸大小作了比较,并对微球的成因进行了初步探讨。     

响应曲面法优化中空介孔羟基磷灰石负载姜黄素的处方工艺

以碳酸钙为模板,在140℃、碱性水溶液中制备出球形度良好且粒度均匀的中空介孔羟基磷灰石微球,并采用溶剂浸渍法负载上模型药物姜黄素,利用扫描电子显微镜、透射电子显微镜、氮气吸附-解吸附、傅里叶变换红外光谱等仪器对微球及其载药体系进行表征。通过三因素三水平的Box-Behnken实验设计(BBD)对微球包载姜黄素的工艺处方进行优化。研究发现,当姜黄素/HMAPs质量比为19.95∶1、载药时间为5.8 h、超声时间为1.48 h时为最优处方工艺,此时载药量理论预测值为73.43%。     

中空铁酸锌纳米材料的制备及其光催化性能

利用碳微球为模板,通过溶剂热法合成中空铁酸锌纳米微球。通过X-射线衍射(XRD)、傅里叶红外光谱(FT-IR)、透射电子显微镜(TEM)、紫外-可见漫反射光谱(DRS)、热失重(TG)和光致发光(PL)等测试手段对催化剂进行表征。选取罗丹明B作为目标染料进行光催化降解实验。结果显示,制备的铁酸锌纳米微球具有明显的中空结构和良好的光催化活性。同时对中空结构铁酸锌微球的形成机理进行了讨论。     

以碳球为模板的核壳型结构的制备与表征

利用表面具有羟基和羧基等活性机团的碳球和铜-碳核壳微球（Cu@C）作为模板,通过一个简单的过程合成各种ZnO的中空结构（包括氧化铜-氧化锌铃铛型中空结构）。该方法在合成氧化铜中空球时具有明显优势。     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。